V418 Ser still bright (superoutburst) YYYYMMDD(UT) mag observer 20210129.7762 <148c (Yutaka Maeda) 20210130.8214 <141c (Yutaka Maeda) 20210203.5034 15.244zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210205.4262 15.711zr (Zwicky Transient Facility Lasair (Masci+ 2019))